The present disclosure is generally directed, in various embodiments, to a process for producing low molecular weight latex. The latex so produced is utilized to generate emulsion aggregation toners. More particularly, the process includes preparing latex having lower weight average molecular weight under a monomer-starved polymerization conditions. The toner particles prepared according to the present disclosure have one or more enhanced properties such as gloss, fusing performance, crease performance, stripping performance, document offset, vinyl offset, parent charging, etc.
In general, E/A (emulsion/aggregation/coalescence) processes are known to fabricate toners. Emulsion polymerization typically comprises forming an emulsion of a surfactant and monomer in water, then polymerizing the monomer in the presence of a water soluble initiator. For example, U.S. Pat. No. 5,853,943, the disclosure of which is totally incorporated herein by reference in its entirety, is directed to a semi-continuous emulsion polymerization process for preparing a latex by first forming a seed polymer. U.S. Pat. No. 5,928,830, the disclosure of which is also totally incorporated herein by reference in its entirety, is directed to a semi-continuous emulsion polymerization process for preparing a latex preparation of a latex polymer with a core encapsulated within a shell polymer, wherein a toner prepared with said latex polymer exhibits good fix and gloss characteristics.
EA toners produced by the above processes or other are generally ultrafine particle toners with precisely controlled particle size, size distribution, and particle shape. General EA processes for the preparation of toners are also illustrated in a number of Xerox patents, the disclosures of each of which are totally incorporated herein by reference, such as U.S. Pat. Nos. 5,290,654; 5,278,020; 5,308,734; 5,370,963; 5,344,738; 5,403,693; 5,418,108; 5,364,729; and 5,346,797. Also of interest may be U.S. Pat. Nos. 5,348,832; 5,405,728; 5,366,841; 5,496,676; 5,527,658; 5,585,215; 5,650,255; 5,650,256; 5,501,935; 5,723,253; 5,744,520; 5,763,133; 5,766,818; 5,747,215; 5,827,633; 5,853,944; 5,804,349; 5,840,462; 5,869,215; 5,869,215; 5,863,698; 5,902,710; 5,910,387; 5,916,725; 5,919,595; 5,925,488; 5,977,210; 5,994,020; 6,020,101; 6,130,021; 6,120,967 and 6,628,102. The disclosures of these patents are also totally incorporated herein by reference.
For some applications in the graphics arts market, high gloss images are desired. For example, styrene/n-butyl acrylate emulsion/aggregation (E/A) toners for certain oil and oil-less fusers such as 80 PPM Belt Fuser fixtures require high gloss images.